1. Field of Invention
The present invention relates to an active device array substrate, a display panel and examining methods thereof. More particularly, the present invention relates to an active device array substrate, a liquid crystal display panel having an inner short ring and examining methods thereof.
2. Description of Related Art
In response to the increasing demand of the display, the industry put efforts in the development of the display. Among the displays, the cathode ray tube (CRT) has occupied the display market for many years, due to its high display quality and mature technology. However, the rising “environmental protection” awareness against its power consumption and radiation disadvantage, and its limited flattening capability against the market demands of light, thin, short, small, chic, and power-saving displays, have limited the growing space of CRTs. Therefore, the thin film transistor liquid crystal display (TFT-LCD), having superior properties such as high image quality, good space utilization, low power consumption and no radiation, has become the mainstream display product of the market.
The TFT-LCD mainly comprises a liquid crystal display panel and a backlight module. The liquid crystal display panel usually comprises a thin film transistor array substrate, a color filter substrate and a liquid crystal layer disposed between the two substrates. And the backlight module is used to provide a surface light source for the liquid crystal display panel, such that the liquid crystal module may achieve the display effect.
The thin film transistor array substrate may be divided into a display region and a peripheral circuit region, wherein a plurality of pixel units are disposed in an array on the display region, and each of the pixel units comprises a thin film transistor and a pixel electrode connected with the thin film transistor. Moreover, a plurality of scan lines and data lines are disposed in the peripheral circuit region and the display region, wherein the thin film transistor of each pixel unit is controlled by the corresponding scan line and data line.
Usually, after the manufacturing process of the film transistor array substrate, an electrical examination is performed on the pixel units on the thin film transistor array substrate so as to determine whether the pixel units work normally. When the pixel units cannot work normally, the defective components (such as the thin film transistor or the pixel electrode) or the circuit can be repaired. However, in order to examine the pixel units, an examining circuit should be fabricated on the peripheral circuit region of the thin film transistor array substrate. It should be noted that, the examining circuit is complicated, and may reduce the layout region on the panel. Furthermore, after completing the examination, the examining circuits are disabled by a laser cutting technology, so as to avoid affecting the display quality of the liquid crystal display panel.
In addition, electrostatic accumulation may occur in the liquid crystal display panel, due to external factors, such as transportation or environment variation. Therefore, when the charges accumulate to a certain amount, the circuit or the thin film transistor on the thin film transistor array substrate may be damaged due to the electrostatic discharge (ESD). To avoid the problem, an ESD protection circuit is usually disposed in the peripheral circuit region of the thin film transistor array substrate.
However, conventionally, to achieve the above examination and electrostatic protection functions, an examining circuit and an ESD protection circuit should be fabricated simultaneously in the peripheral circuit region of the thin film transistor array substrate. As a result, the layout of the peripheral circuit becomes more complicated, thus resulting in insufficient layout space, which works against the simplification of the manufacturing process and the improvement of the production efficiency.